Fair Value - Changes in FV under the FV Option (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses)	$ 480	$ 204
Loans
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses)	(45)	71
Long-term debt:
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses)	$ 111	$ (269)

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-30

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-31

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-32

Name:	us-gaap_FairValueOptionQuantitativeDisclosuresLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration